It is known in the art relating to crankcase scavenged two cycle engines that cylinder and wrist pin lubrication may be accomplished by mixing lubricating oil with the air drawn into the engine crankcase, compressed and forced into the cylinder for scavenging and charging the cylinder. The lubricating oil lubricates the cylinder walls and pistons as well as the crankshaft and wrist pin bearings and much of it is subsequently burned along with the fuel in the engine cylinder.
However, the unburned oil adds significantly to unburned hydrocarbons (HC) in the engine exhaust and makes difficult the use of such an engine for emission controlled automotive vehicles. Pressure scavenging with a pump separate from the crankcase can allow the use of conventional wet sump oil storage and pressure distribution and largely avoid the problem of oil carryover into the cylinder but crankcase scavenging is thought to have advantages in simplicity and performance which make its use desirable. An alternative means for lubrication of the bearings and cylinders is therefore desired.